The applicant of the present invention is also the applicant of other patents belonging to the same field of the art and has been developing clamps for pipes and sleeves since the mid-twentieth century seeking both to improve the models that from their own experience are susceptible to be improved and to create new products with greater efficiency.
Nowadays, clamps are required to meet ever stringent standards and, as a result of that, the improvements introduced occasionally relate to specific aspects of same, like in the present case, where the inventive emphasis is placed on the function of mutual guiding of the two ends of the clamp and obtaining a firm and secure fastening thereof, which should at the same permit disassembling of the clamp. That is to say, despite the fact that this is a very powerful locking that can undergo highly elevated tensions, its particular arrangement makes it possible for the clamp to be easily disassembled.
The clamp of the invention, in its fastened condition, is provided with means for clamping. To that goal, it includes a deformation bridge having means for guiding said deformation and for reinforcing its inertial tension. It is also provided with a tongue located at one of the ends of the clamp that permits easy guiding and engagement of said tongue with a stepped projection located at the opposite end of the clamp, which makes it possible to obtain a closed clamp devoid of steps that may damage pipes or hoses once the two ends of said clamp have become superposed after one of the ends has moved into the cavity created in the body of the other end. For instance, a deformation bridge like the one described in patent ES2223220 to Mikalor, S. A. can be used.
There are many examples in the prior art describing clamps of the type of the present invention that utilize butt ends, flanges and hooks which are obtained by stamping of the strip and are inserted in orifices provided at the other end. That is the case of utility model ES042946U, ES149843U and ES260128U, amongst many others.
Utility model ES257615U describes hooks obtained by stamping of the strip and further lifting of a portion of said strip, said hooks, upon fastening of the clamp, being inserted into opposed orifices provided at the other end of the strip.
Another example of already disclosed art is utility model ES257616U, in which flanges formed by stamping of the strip and further lifting of material are inserted into orifices provided at the other end of the strip.
European patent EP00946790 develops means for open clamp hooks for preventing disengagement of the connection during the tightening operation of the clamp, said hooks having two folds, so that a first oblique portion that projects externally relative to the surface of the strip is followed by another portion that runs approximately parallel to the strip and terminates in another oblique portion that projects outwardly of the strip.
Said embodiment may be provided with, either flat hooks having an inverted “L”-shaped section, or hooks obtained by stamping of a portion of the strip surface and further lifting along its side in the longitudinal direction of the strip until reaching a position perpendicular to same, where said profile can be obtained by performing appropriate staggered cuts.
U.S. Pat. No. 5,274,886 describes hooks also having a staggered working profile, although in this patent said hooks are used for pre-mounting a clamp that is modified by the definitive closing with a different use from that of patent EP00946790.
It is also known the provision of inverted “L”-shaped hooks, like in U.S. Pat. No. 4,492,004, in order to hinder accidental disengagement of said hooks during tightening of the clamp, although negative bending is not precluded due to the elevated forces applied for constraining present-day clamps.
As for the embodiment of patent EP00946790, it allows a first contact between the edge of the orifice into which the hook is inserted and the outermost surface of said hook during mounting operation of the clamp, so that when tightening of the clamp is underway the hook tends to slide along that side until it ends up engaged in the first inclined profile. At this stage, all the elements forming the clamp help to avoid disassembling of said clamp in a similar manner to the way the shape of the hook helps to prevent its negative folding.
However, the drawback of such a construction is that, as it occurs with clamps provided with a hook having one single inclined projection, the edge of the orifice can become blocked at any height and the engagement of all the elements responsible for fastening the clamp is not attained during pre-mounting of said clamp, and the same happens here with the third projection, which only proves to be useful for providing a greater mechanical resistance to the hook resulting from its ensuing greater surface.
As for the applicants of the present invention, they developed in their patent ES2126434 improvements to means for fastening intended to obtain greater clamping forces for clamps. For instance, for clamps affixed about pipes made from stiff plastic for which the high tightening forces that are required cannot be withstood by traditional fastening means.
According to the improvements of the aforesaid invention, two stamped portions are embedded in the opposite strip, this being similar to a clinching operation, which results in a clamp that is supplied in an already closed condition and that cannot be disassembled without precluding its breakage.
Performing cuts and deformations on the strip surface with the ensuing tunnels or recesses on said surface is also widely known. Patent U.S. Pat. No. 4,299,012, amongst many others, resorts to one of these constructions for guiding the clamp tongue during the process of constriction, thereby obviating discontinuities on the inner surface of the clamp.
Patent U.S. Pat. No. 4,492,004 discloses a construction that relates two tunnel-like strip deformations that extend one inside the other as means of support for the closing tools and means for constricting certain clamps that are provided with no such means of constriction. Said clamps are usually provided with hooks that perform the fastening or initial mounting of the clamp and other elements or positions of same for the definitive closure once the clamp has been constricted.
Patent EP0816740, for instance, uses said tunnels for tightening the clamp and also includes a hook obtained by stamping of the strip and further lifting of said hook along its side that coincides with the longitudinal direction of the strip, which is of a type similar to that of the present invention.
The above-mentioned clamp is not provided, like the one disclosed in patent EP00946790, with a hook having an edge with three projections. Such hook, that is conceptually similar to traditional inverted “L”-shaped hooks, has only two projections, one of which is a guiding projection that is inclined in the direction of the strip surface, and another one that runs vertical to said strip and defines the butt end at the edge of the orifice into which the hook is inserted.
The clamp disclosed in the present invention, since it is of the open type that is constricted by deforming the limbs of a Mikalor type bridge, as described in patent ES2223220, is mounted by engaging the hook in its corresponding orifice.
Said operation, due to the manner in which the hook and the orifice, which are closely related to each other, come into contact, optimizes the guiding function of one end of the clamp along the other in order to engage the retaining pawl with its respective retaining bridge, that is used as a retainer during mounting of the clamp and prior to its constriction.
The purpose is to obtain for the mounting operation of the clamp an optimal engagement of all its elements, so that when constraining of the clamp is underway by means of a pneumatic percussion wrench, for instance of the “unitary effort” type developed by Mikalor in patent ES2220182, which imparts considerable tension on the elements of the clamp, all of said elements can help in the fastening operation, thereby keeping the clamp from “springing” and become unfastened, and hence avoiding at the same time the proliferation of different fastening elements that make the clamp more expensive, render its manufacture more difficult and accentuate the irregularity of its surface with the ensuing increase in the number of cutting points with respect to its surrounding area.
Although the clamp can be supplied in a fully open condition, in order to economize storing space, it can also be supplied in a pre-formed condition and having a circular position, so as to facilitate coiling of the clamp about the hose or pipe on which it is used. The clamp can even be supplied in a pre-mounted condition, so that operators only have to manually disengage the hook at the other end of the clamp, place it about the pipe on which it is applied and close it again by engaging the hook in its corresponding orifice.
Once the clamp is mounted, thanks to the inclined mutual contact surfaces both of the orifice and the hook, it is also attained and optimal engagement of the retaining pawl with the retaining bridge that will for the most part withstand the force with which the Mikalor bridge is constrained.
The clamp, upon constriction, might be disassembled by disengaging the hook from its orifice with the aid of a suitable tool, with the ensuing advantages of the present invention, that is, obtaining a demountable clamp that does not need to be broken and is capable of withstanding high tightening forces with a reduced number of elements.
It is therefore a main object of the present invention to obtain a clamp with highly resistant fastening means that permits high clamp constricting forces using a reduced number of elements.
It is another main object of the invention to provide a clamp that permits easy mounting by an operator, with no need for the clamp to be supplied in its pre-mounted condition at the manufacturing plant.
It is another of the main objects of the invention that the above-described clamp can be disassembled without having to break it.
It is still another main object of the present invention to provide guiding means that help the operator assemble the clamp prior to its constriction.